Climate scientists have painted a pretty grim outlook for our planet in the wake of an unabated release of greenhouse gases into the atmosphere -- from rising sea levels and increasing weather disasters, to resource shortages and mass extinctions -- but there's one side effect of global warming sure to make you go 'aww'. According to paleontologists, an early species of horse was discovered to have responded to an extended bout of unusually hot temperatures million years ago in the most peculiar of ways: by going miniature. And given the steamy future which may be in store, it could happen again -- this time, to your quite-possibly-mini great-great-grandkids.

For 175 thousand years, due to a rise in global temperatures 58 million years ago known as the Paleocene-Eocene Thermal Maximum, one of the first equestrian species to gallop the planet underwent a dramatic change in size. During this period, a higher than normal levels of atmospheric carbon dioxide lead to hotter planet, and in response fossil evidence of shows that an early ancestor of the horse, Sifrhippus, shrunk to the size of a house cat. Other species, say researchers, even halved in size to accomodate the hot spell.

In addition to this, many animals will probably die out or have their population significantly reduced.

_________________"In My view, all that is necessary for faith is the belief that by doing our best we shall come nearer to success and that success in our aims (the improvement of the lot of mankind, present and future) is worth attaining."- ROSALIND FRANKLIN

I want to develop methods of raising smaller meat animals for a number of reasons but now I can add a possible hot future to the list of reasons for going small. Another interesting thing about small animals is that most use the dirt to moderate the temperatures in some way (usually by underground homes but other uses too). My concentration is on burrowing species but for completely unrelated reasons... could also be functional for urban livestock in city back yards turning grass and weeds into high protein meat. Recent genetic studies suggest that guinea pigs were raised as meat animals as long as sheep and cattle have been... you just have to get used to eating cute.

I heard that warmer weather affects animals in utero causing smaller ones to have a higher chance of living, but I can't find the source.

_________________"In My view, all that is necessary for faith is the belief that by doing our best we shall come nearer to success and that success in our aims (the improvement of the lot of mankind, present and future) is worth attaining."- ROSALIND FRANKLIN

The smaller ones needed less food and less food was available. PETM was about ten times slower than what is happening now, and many more species had time to adapt. This "event" has more methane to "turn over", too. Anthropocene Epoch Thermal Maximum will occur in 300 to 1200 years with an extinction rate of ~87% from the amount of species present at the beginning of this interglacial.The recovery time will be greater than PETM, at least 200K years, with several million to regain biological diversity. I doubt if any humans will make it through this bottleneck.If the Yellowstone Super Volcano erupts significantly before AETM, it 'could' cancel out thermageddon. A nuclear winter could affect things, too. Disruption of the Gulf Stream also could affect Northern Hemisphere albedo, perhaps enough to stop it, too.It will assuredly be a harsher world for the survivors of the guaranteed population crash circa 2050 (2030s to 70s), and people will continue burning excessive amounts of fossil fuels until then. Tundra methane self release is probably already happening and accelerating.

_________________"With every decision, think seven generations ahead of the consequences of your actions" Ute rule of life.“We do not inherit the earth from our ancestors; we borrow it from our children”― Chief Seattle“Those Who Have the Privilege to Know Have the Duty to Act”…Albert Einstein